I. Field of the Invention
The present invention relates to a two-part fastening system, consisting of an anchoring part having a support plate and a fastening part which is provided with elastically deformable clamping walls which may be pressed onto the anchoring part.
II. Description of the Prior Art
Two-part fastening systems which may be pressed together are known, such as the system disclosed in German Patent DE 34 06 934 Cl. This fastening system includes a holding part for securing an object and a nut-like fastening part. The holding part has a threaded pin and the fastening part has a plurality of smooth resilient clamping walls. The clamping walls are pressed on to the threaded pin to slide over the pins of the holding part. Once in place, the edges of the threads of the pin cut into the clamping walls slightly to provide a generally secure connection. The threaded pin may be removed from the fastening part by unscrewing the pin from the holding part.
It is possible to produce holding parts with anchoring portions, such as T-bolts or threaded pins, with a plastic carrier or support plate. In order to injection mold the holding parts with the support plate in one operation, it is necessary to use relatively complicated and expensive injection molding machines. However, the performance of such machines is below that of those using simple casting molds which permit removal of the part on one plane. Alternatively, it is possible to use casting molds for injection molding the anchoring parts.
Another solution lies in casting the support plates without the anchoring parts and fastening the anchoring parts to the carrier in a second operation, for example by cementing, friction welding, or interference fit. This solution has the disadvantage that the anchoring parts have to be manufactured separately and mounting the assembly to the carrier requires extra resources and additional time, which results in substantial additional costs.
Thus, an object of the invention is to form a fastening body with an associated anchoring part in such a manner that both can be economically injected and removed from the mold without problems. A further object of the invention is to design the cooperating fastening member in such a way as to provide stronger holding forces between the parts.
These objects are achieved in a simple manner by providing a fastening member having a pair of clamping walls having sharp, pointed projections which engage a plurality of ribs formed on an anchoring member. This arrangement provides a large increase in the holding forces.
A first preferred embodiment of the invention includes an anchoring part having a webbed plate onto which a fastening body is pressed. The fastening body has two parallel clamping walls with sharp, pointed projections which securely lock the two parts together.
Also disclosed is an alternative preferred embodiment of the invention including an anchoring part in the form of a ribbed bolt and a fastening member having a sleeve having sharp, pointed circumferential projections in two diametrically opposed regions. The sleeve is first pressed axially onto the bolt and then the projections and ribs are brought into engagement by rotation of one part a quarter turn relative to the other part.